Digital or solid state lighting technologies, i.e., illumination based on semiconductor light sources, such as light-emitting diodes (LEDs), offer a viable alternative to traditional fluorescent, high-intensity discharge (HID), and incandescent lamps. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, durability, lower operating costs, and many others. Recent advances in LED technology have provided efficient and robust full-spectrum lighting sources that enable a variety of lighting effects in many applications.
Some of the fixtures embodying these sources feature a lighting module, including one or more LEDs capable of producing white light and/or different colors of light, e.g., red, green and blue, as well as a controller or processor for independently controlling the output of the LEDs in order to generate a variety of colors and color-changing lighting effects, for example, as discussed in detail in U.S. Pat. Nos. 6,016,038 and 6,211,626, incorporated herein by reference. LED technology now enables line voltage powered white light fixtures, such as the EssentialWhite™ series available from Philips Color Kinetics. These fixtures may be dimmable using trailing edge dimmer technology, such as electric low voltage (ELV) type dimmers for 120VAC line voltages.
However, conventional solid state white light fixtures, including LED white light fixtures, are input voltage dependent. Thus, the various types of solid state white light fixtures operate only at specific line voltages for which they are respectively designed. The value and frequency of the line voltages may differ, depending on various factors, such as geographic location of the user (e.g., U.S. markets typically require a 120VAC, 60 Hz line voltage while European markets typically require a 230VAC, 50 Hz line voltage) and physical location of the installed solid state white light fixture (e.g., fixtures installed in high alcoves typically require 277VAC line voltage while fixtures installed in under-cabinet environments typically require 120VAC line voltage).
Such operational differences among the various types solid state white light fixtures cause confusion and practical inefficiencies for manufacturers and users. For example, electrical contractors typically must have multiple sets of inventory on hand corresponding to the number of different line voltages available in a particular construction project. The sets of inventory must be carefully managed through installation, or new LED white light fixtures may be ruined by application of an incorrect input line voltage. In addition, while LED white light fixtures designed to run at different input line voltages may have the same printed circuit boards, other components differ based on design differences needed to accommodate operation at 100VAC, 120VAC, 230VAC or 277VAC input line voltages, for example. This is inefficient from a supply chain and manufacturing perspective, since each input line voltage requires its own custom bill of materials, stock keeping units, and the like. Managing this has proved troublesome, as it is difficult to forecast demand. Therefore, marketing, supply chain and manufacturing would benefit from an LED white light or other solid state lighting fixture having a universal voltage input.